Neuromodulation specific to objective function of modulation field for targeted tissue

Abstract

An example of a system may include electrodes on at least one lead configured to be operationally positioned for use in modulating a volume of neural tissue, where the neural tissue has an activation function. The system may further include a neural modulation generator configured to deliver energy using at least some electrodes to generate a modulation field within the volume of neural tissue. The neural modulation generator may be configured to use a programmed modulation parameter set to generate the modulation field. The programmed modulation parameter set having values selected to control energy delivery using the at least some electrodes to achieve an objective function specific to the activation function of the volume of neural tissue to promote uniformity of a response to the modulation field in the volume of neural tissue along a span of the at least one lead.

What is claimed is: 
     
       1. A method for modulating a volume of tissue to promote uniformity of a modulation response in the volume of tissue, wherein the volume of tissue has an activation function characterizing the volume of tissue's response to electrical modulation, the method comprising:
 selecting, using a user interface, a modulation field to electrically modulate the volume of tissue that has the activation function, wherein selecting the modulation field includes selecting an objective function for the modulation field that is specific to the volume of tissue and the activation function of the volume of tissue to promote the uniformity of the modulation response in the volume of tissue to the modulation field, wherein the objective function identifies characteristics of the modulation field for modulating the volume of tissue; 
 programming a neuromodulator with modulation parameters determined, using both the objective function and the activation function, to promote the uniformity of the modulation response in the volume of tissue; and 
 using the neuromodulator programmed with the modulation parameters to modulate the volume of tissue using the selected modulation field with the selected objective function specific to the volume of tissue and the activation function of the volume of tissue to promote the uniformity of the modulation response in the volume of tissue. 
 
     
     
       2. The method of  claim 1 , wherein selecting the objective function for the modulation field includes selecting an objective function to modulate dorsal horn tissue. 
     
     
       3. The method of  claim 2 , wherein selecting the objective function for the modulation field further includes selecting a constant E objective function to modulate the dorsal horn tissue. 
     
     
       4. The method of  claim 2 , wherein selecting the objective function for the modulation field further includes selecting a constant |E|objective function to modulate the dorsal horn tissue. 
     
     
       5. The method of  claim 1 , wherein selecting the objective function for the modulation field includes selecting an objective function to modulate dorsal column tissue. 
     
     
       6. The method of  claim 5 , wherein selecting the objective function to stimulate dorsal column tissue includes selecting a constant activation function to modulate dorsal column tissue. 
     
     
       7. The method of  claim 6 , wherein selecting the constant activation function to modulate dorsal column tissue includes selecting a constant voltage to modulate dorsal column tissue. 
     
     
       8. The method of  claim 1 , wherein selecting the objective function for the modulation field includes:
 selecting a dorsal horn objective function to modulate dorsal horn tissue; and 
 selecting a dorsal column objective function to modulate dorsal column tissue. 
 
     
     
       9. The method of  claim 1 , wherein:
 the volume of tissue has an activation function for an electrical modulation parameter that is proportional to an n-order spatial derivative of the electrical modulation parameter; and 
 selecting the objective function for the modulation field includes selecting a constant objective function for the n-order spatial derivative of the electrical modulation parameter, the selected constant objective function to promote uniformity of a modulation response in the volume of tissue. 
 
     
     
       10. The method of  claim 1 , further comprising determining fractionalization values for each active contact to provide the selected modulation field that meets the selected objective function, wherein programming the neuromodulator with modulation parameters incudes programming the neuromodulator with the fractionalization values. 
     
     
       11. A method for modulating a volume of tissue to promote uniformity of a modulation response in the volume of tissue, wherein the volume of tissue has an activation function characterizing the volume of tissue's response to electrical modulation, the method comprising:
 selecting, using a user interface, a modulation field to electrically modulate the volume of tissue, wherein selecting the modulation field includes selecting an objective function for the modulation field that is specific to the volume of tissue and the activation function of the volume of tissue to promote the uniformity of the modulation response in the volume of tissue to the modulation field, wherein the objective function identifies characteristics of the modulation field for modulating the volume of tissue; 
 determining fractionalization values for each active contact to provide the selected modulation field with the selected objective function, and programming a neuromodulator with the fractionalization values to promote the uniformity of the modulation response in the volume of tissue; and 
 using the neuromodulator programmed with the fractionalization values to modulate the volume of tissue using the selected modulation field with the selected objective function specific to the volume of tissue and the activation function of the volume of tissue to promote the uniformity of the modulation response in the volume of tissue. 
 
     
     
       12. The method of  claim 11 , wherein determining fractionalization values for each active contact includes:
 estimating a unit field for each active contact using an electric field model, the estimated unit field being the field induced when the respective active contact is energized with an energy unit; 
 determining weighted unit fields, including determining a perception threshold for each active electrode and calibrating the estimated unit field for each active electrode using the respective perception threshold; 
 forming constituent source(s) for the active contacts, each of the constituent sources including an electrical contact to provide a source and another electrical contact to provide a sink; 
 constructing a transfer matrix using the weighted unit fields for the constituent sources; 
 solving for contributions from each constituent sources to provide the selected modulation field; and 
 computing fractionalization values for each active contact from the solution for the constituent sources. 
 
     
     
       13. The method of  claim 12 , further comprising selecting active electrodes from a plurality of electrodes on at least one lead. 
     
     
       14. The method of  claim 11 , wherein selecting the objective function for the modulation field includes:
 selecting an objective function to modulate dorsal horn tissue; and 
 selecting the objective function for the modulation field includes selecting a constant E objective function to modulate the dorsal horn tissue, or selecting a constant |E|objective function to modulate the dorsal horn tissue. 
 
     
     
       15. The method of  claim 11 , wherein selecting the objective function for the modulation field includes:
 selecting an objective function to modulate dorsal column tissue; and 
 selecting a constant voltage to modulate dorsal column tissue. 
 
     
     
       16. A non-transitory machine-readable medium including instructions, which when executed by a machine, cause the machine to modulate a volume of tissue to promote uniformity of a modulation response in the volume of tissue, wherein the volume of tissue has an activation function characterizing the volume of tissue's response to electrical modulation, including:
 receive a selection of a modulation field to electrically modulate the volume of tissue, including receive a selection of an objective function for the modulation field that is specific to the volume of tissue and the activation function of the volume of tissue to promote the uniformity of the modulation response in the volume of tissue; 
 determine modulation parameters for use by a neuromodulator to modulate the volume of tissue, using both the objective function and the activation function, to promote the uniformity of the modulation response in the volume of tissue, and 
 program the neuromodulator with the modulation parameters to modulate the volume of tissue using the selected modulation field with the selected objective function specific to the volume of tissue and the activation function of the volume of tissue to promote the uniformity of the modulation response in the volume of tissue. 
 
     
     
       17. The machine-readable medium of  claim 16 , wherein the objective function includes a constant E objective function to modulate dorsal horn tissue. 
     
     
       18. The machine-readable medium of  claim 16 , wherein the objective function includes a constant |E|objective function to modulate the dorsal horn tissue. 
     
     
       19. The machine-readable medium of  claim 16 , wherein the objective function includes a constant |E|objective function to a constant voltage activation function to modulate dorsal column tissue. 
     
     
       20. The machine-readable medium of  claim 16 , wherein the instructions include instructions, which when executed by a machine, cause the machine to determine fractionalization values for each active contact to provide the selected modulation field that meets the selected objective function, wherein the fractionalized values for each electrode are used to deliver the selected modulation field with the selected objective function.